Oklahoma State University

This is a Before Class Exploration on stoichiometry. To answer the questions on this BCE it is OK to use your textbook, but if you can answers the
questions without it that is OK too.

Answer all of the questions below. If you
do not know an answer enter CNA. However, it will help the most if you answer
each question with your best intuition/idea about what would be a reasonable
answer.

First Name:

Last Name:

School:

In this BCE we will investigate a chemical reaction as viewed at the particulate level. In Table I below are three experiments that you are to perform using a simulation of a chemical reaction. Click on the link for Exp #1. When the simulation appears in a new window, resize the window to allow you to see the simulation and this BCE window. After resizing the window note the number and kind of reacting particles, then click on the Enable Reaction button and then the Resume button; (Note you may want to reduce the volume of the container if the reaction is too slow.)

Table I.

Experiment

Reactant1 (R)

Reactant2 (GB)

4

4

NOTE: If you the simulation does not load (you see an X) after clicking the link above go to http://java.com/en/ and follow the instructions. We will be using these types of simulations many times this semester and next. You may also view the Exp#1 as a movie, if the Java Applet does not load.

Briefly describe what you observed happening in the reaction container Before and then After clicking on the Enable Reaction button. (NOTE: Use words like molecules atoms, collision, velocity, reaction, reactants and products.)

To summarize what happens in the simulation for Exp #1 look at Table II. which has been completed as an example.

Table II: Experiment #1.

REACTANTS

REACTANTS

PRODUCTS

PRODUCTS

Exp. #1

Reactant(1)

Reactant(2)

Product(1)

Product(2)

Formula

R

BG

--->

RG

B

Initial Amount

4

4

0

0

Change Amount

-4

-4

+4

+4

Final Amount

0

0

4

4

How many Red atoms were present initially?

How many Red atoms reacted?

How many RG molecules were formed?

Now perform Experiment #2 - #3: To access each experiment click the mouse on the Exp # link below. This will open a new window containing a reaction container. Complete Table II for Exp#2 and #3 in the same way as Table II for Exp #1 above.

Experiment

Reactant1 (R)

Reactant2 (GB)

4

2

2

4

Reminder Instructions: Enter the formula for each reactant (recommend using the capitalized first letter for the color(s) of the particle as it formula, for example R and BG) and the initial amount of each reactant in Table II: Experiment #2 or #3. After recording this information for the particular experiment (#2 or #3) in the appropriate table, click on the Resume Button and then click on the Enable Reaction button and then observe what takes place in the reaction container. After the reaction is 'complete' enter the formula(s) of the product(s) of the reaction in the table. Also enter the final amounts of the reactants and the product(s) in the table.

Table II: Experiment #2

REACTANTS

REACTANTS

PRODUCTS

PRODUCTS

Exp. #2

Reactant(1)

Reactant(2)

Product(1)

Product(2)

Formula

--->

Initial Amount

Change Amount

Final Amount

Table II: Experiment #3.

REACTANTS

REACTANTS

PRODUCTS

PRODUCTS

Exp. #3

Reactant(1)

Reactant(2)

Product(1)

Product(2)

Formula

--->

Initial Amount

Change Amount

Final Amount

Write a balanced chemical equation describing the reaction you observed in each experiment. (Use a format similar to R1 + R2 --> P1 + P2 when writing the equation for the reactions observed. Use a single space to separate reactants, products, plus sign and the reaction arrow.)

Exp. #1:

Exp. #2:

Exp. #3:

A reagent in excess is a reactant that is not completely used up in a chemical reaction, a limiting reagent is a reactant that limits the amount of product formed in a chemical reaction. Look back at Table II Exp#1, #2 and #3 and select one of the radioboxes below that best fits the assignment of the excess reagent and the limiting reagent.